Recommend WSL on Windows 10

At this point, I consider the batch scripts @IBNobody and I worked on to mostly be a failure. They've proven to be unreliable, too dependent on the environment they're being run in, and I've seen far too many examples of people having frustrating issues with them that I haven't been able to help them with. They can also produce misleading and confusing error messages. I've been pointing people to use the WSL for a while now. Eventually, I think we should make a proper replacement for the batch scripts, possibly with an environment in msys2. For now, the WSL method in Windows 10 is far more reliable, and is easy to set up. 

I also cleaned up some things in the WSL instructions themselves.